Pipe coupling



July 26, 1949. J. c. HOBBS Re. 23,137

PIPE COUPLING Original Filed Aug 15, 1944 2 Sheets-Sheet 1 v 39 35 INVENTOR.

}30 32 3/ J7] MES 0/1 0555 y 1949- J. c. HOBBS Re. 23,137

PIPE COUPLING Original Filed Aug. 15, 1944 2 Sheets-Sheet 2 III IHHHIIHIIIIIIIIHIIHHI mm! is 5 H INVENTOR. JA M55 0. #0555 US: B 7' M 80 E 958/ 6 3 $6128 TmiP/VEYS Reiuued July 26, 1949 UNITED STATES PATENT OFFICE No. 549,533, August 15, 1944.

Application for reissue May 26, 1949, Serial No. 95,565

I Cl. 285-86) 7 Claims.

This invention relates generally to fluid seals and more particularly to new seals for the ends of pipes carrying fluids under high pressure.

A great many efforts have been made heretofore to prevent the escape of fluids at the ends of pipes, as in pipe couplings, joints and the like. Some of the seals proposed were fairly satisfactory in sealing against escape of low pressure fluids while other seals were fairly satisfactory in sealing thick walled pipes against escape of fluid under fairly high pressure. Most of the prior high pressure seals were heavy, cumbersome and expensive, and few, if any, of them were capable of sealing fluid pressures on the order of 1500 pounds per square inch or more when sub- Ject to rapid temperature changes.

The present invention provides a simple, light, inexpensive seal which is capable of sealing against escape of fluids whose pressures range all the way up to 10,000 pounds per square inch or more. Such seals may be used with pipes whose thicknesses range from a very thin wall such, for example, as 0.02 inch up to heavy walls such, for example, as several inches. Furthermore, the sealing effect of seals embodying the present invention increases with increases in force tending to separate the pipe axially from its associated member and also increases with increases in the sealing force applied to the seal. From what has just been stated it will be apparent that the present invention provides a new seal which is capable of many different applications and which is not only better in many respects than prior seals but is much more effective in operation. Furthermore, as will be pointed out more in detail hereinafter, the mode of operation of seals embodying the present invention is new and different from the modes of operation of all other prior seals with which I am familiar.

In the drawings accompanying and forming a part of this specification and showing various forms of apparatus embodying this invention,

Figure 1 is a fragmentary, sectional view showing a seal at the Junction of a pipe end and a hollow member extending transversely to the longitudinal axis of the pipe;

Figure 2 is an enlarged view of parts of Fig. 1;

Figure 3 is a fragmentary, sectional view similar to Fig. l, but showing a modified form of seal;

Figure 4 is a fragmentary, cross-sectional view of a seal between a pipe end and an aligned coupling;

Figure 5 is a view similar to Fig. 4 but showing a modified form of pipe end and sealing ring;

Figure 6 is a fragmentary, cross-sectional view of a seal at the telescoped ends of two pipes, one of which is flanged;

Figure 7 is a fragmentary, cross-sectional view of a seal at the junction of a flanged coupling and a pipe end and illustrating the application of forces to the seal and the effect of those forces on the sealing action of the device;

Figure 8 is a fragmentary, cross-sectional view resembling Fig. 7 in certain respects but illustrating the resolution of sealing forces by the threads on the flanged coupling;

Figure 9 is a view similar to Fig. 7 but showing deformable packing in conjunction with the sealing ring; and

Figure 10 is a view similar to Fig. 9 but showing a modified pipe end and sealing ring with deformable packing;

In Figs. 1 and 2 the pipe I has an outwardly flared portion 2 near one end and a concentric lip 3. The outer surface 4 of portion 2 is conical with the base of the cone being nearer the end of the pipe. The conical surface 4 is inclined at an angle of approximately 45 degrees to the longitudinal centerline of the pipe.

The member 5 extends transversely to pipe I and has a. longitudinal passage 6 and a side passage l. The face of member 5 opposed to pipe I is provided with an annular groove 8 around passage 1 and defined in part by radially spaced inner and outer surfaces 9 and I0. The lip 3 of pipe I extends into this groove 8 and may be supported on the inner surface 9 against forces applied to the exterior of pipe I by the sealing ring. Surface I0 is extended outwardly to surround the conical surface 4 on pipe I and to define therewith an annular space II which is wedge-shaped or triangular in cross-section.

The annular pad I2, constituting part of member i. is provided with a plurality of threaded openings to receive studs I3. Retaining and sealing ring I4 is provided with a corresponding number of openings to receive studs I3 and may be urged toward member 5 by nuts I5 on the studs.

Ring II is provided with an annular flange Iii which has a substantially cylindrical outer surface and an annular depression Il near its free end. A sealing ring I8, which may be composed of softer metal than that of the pipe I or memher 5, is disposed in depression l1 and secured to flange I6. The end surfaces of ring III and flange I6 form a conical surface Ill which is inclined at an angle of approximately 44 degrees to the iongitudinal centerline of pipe I. The base of the conical surface I! is at or near the thin edge of flange i8 and is engageable with the conical surface 4 near its base.

When the pipe I, member 5 and ring i8 are assembled substantially as shown in Figs. 1 and 2, and the nuts l5 are turned on studs I! so as to force flange it into the annular space between surface ll of member I and conical surface 4 of pipe i, the flange It will be deflected outwardly so that the outer surface of the ring I! will make substantially a line contact with surface II and the conical surface l9. It will also make substantially a line contact with conical surface I. These two lines will lie in substantially the same plane transverse to the pipe I. These line contacts constitute effective seals against escape of fluid under pressure between those surfaces. The angularity of annular space H which is defined by surfaces 4 and I9 is the difference between the 45 degrees of surface 4 and the 44 degrees of surface l9, or approximately one degree. One important advantage of a small space of approximately one degree is that the sealing contacts may be narrow and, therefore, fluid tight and that they may increase in width under increasing pressure, but as the pressure increases the deflection of the sealing member is resisted more and more strongly and over wider and wider areas until the conical surface of that member may make contact for substantially its full axial length with the opposed conical surface. However, this is an extreme and exceptional condition.

While pipe I is shown as having a wall of substantial thickness, it will be understood that the pipe wall may be much thinner than that illustrated, for the support. afforded by surfac 9 of groove 8 will strongly resist any tendency of the pipe end to deform under pressure applied thereto by ring II.

In Fig. 3 member 20 corresponds generally to member 5 of Fig. 1 but has an annular thread carrying flange 2| and a retaining ring 22 having threaded engagement in flange 2|. The pipe 23 has a thickened end 24 and a conical surface 25 inclined at an angle of approximately 45 degrees to the centerline of pipe 28 and with the base of that surface being nearer to the end of the pipe. The seal ring 26 has an outer surface 21 to engage the opposed cylindrical surface 28 in member 20. abuts at its thick end against threaded ring 22 and has a conical surface 29 extending from its thin end toward the thick end at an angle of approximately 44 degrees to the centerline of pipe 22.

The sealing action of the apparatus of Fig. 3 is substantially like that of the apparatus of Figs. 1 and 2.

In Fig. 4 the pipe 39 has a flared end 2i whose outer surface I! is conical and is inclined at an angle of about 20 degrees to the longitudinal centerline of the pipe, with the base of the conical surface being nearer to the open end of the pipe and whose inner surface rests on the inner inclined surface 28 of coupling 34. That couplin has an annular flange portion 35 threaded interiorly to engage with an exteriorly threaded retaining ring 2| which abuts against the thick end of seal ring 31. The latter ring has an outer substantially cylindrical surface 38 and an inner conical surface 29 whose base is located near the thin end of the ring and whose inclination is approximately 18 degrees to the longitudinal centerline of pipe 30. At its thick end ring 21 has a substantially cylindrical surface 40 whose diameter is only slightly greater than the outside diameter of pipe 20.

When the parts are assembled as shown in Fig. 4 and ring 28 is rotated to urge seal ring 21 toward the right, the inner surface 29 of ring 31 makes substantially a line contact with the opposed conical surface 39 of pipe Ill and the ring is deflected into substantially a line contact of its outer surface 38 with the opposed surface of the coupling. These two substantially line contacts are approximately in a plane at right angles to the longitudinal centerllne of pipe 30 and afford good seals to prevent escape of fluid under pressure from the interior of pipe 30 and past ring 31. The surface 33 of coupling 24 afl'ords internal support adequate to prevent the crushing or distortion of the pipe and even when the pipe has a very thin wall and when the pressure exerted thereon by ring 31 is heavy.

The apparatus of Fig. 5 closely resembles that of Fig. 4. The major differences are that the annular groove ll in coupling 42 has an inner wall 42 near its bottom which is substantially cylindrical; the flared end 44 of pipe 42 has a cylindrical lip 45 to seat on surface l3; and the seal ring 48 is a little larger in inside diameter than the outside diameter of pipe ll, so that normally there is no engagement of the thicker end of ring it with the outer surface of the pipe.

The seal ring 46, when pressure is exerted thereon by the retaining ring, makes substantially line contacts on its outer and inner surfaces with the coupling 42 and the conical surface of the flared portion .4 of pipe 48, and these lines of contact are located in substantially the same plane transverse to the longitudinal centerline of the pipe.

In Fig. 6 the end of pipe 58 is flanged, as at Land is provided with an annular recess 52 having a substantially cylindrical inner side surface 53. The flange 5! is provided with threaded openings to receive studs 54 carrying nuts 55. The end of pipe 58 has a lip 61 to enter groove 52 and a substantially cylindrical surface in engage with surface 53. The outer surface 58 of lip 51 is substantially conical and is inclined at an angle of approximately 45 degrees to the longitudinal center line of pipe hand when the lip is in the assembled position shown in this figure this conical surface is opposed to a substantially cylindrical surface 59 of flange 5|, and, together therewith, partly defines an annular space substantially triangular in crosssection.

Retainer ring 60 has a plurality of openings through which studs I4 pass and is provided with a seal flange 6| which is generally triangular in cross-section and which may extend into the annular triangular space between surfaces 58 and 59. The surface 02 of flange 6| Opposed to surface 58 and pipe 54 is conical, is inclined at an angle of about 44 degrees to the longitudinal center line of pipe I, the bases of conical surfaces 58 and 62 being disposed in substantially the same plane transverse to the longitudinal center line of the pipe I.

when the nuts 55 are turned on studs 54 to urge ring ill toward flange ii, the conical surfaces II and 82 makea substantially line contact and a similar contact is made between the outer surface of seal flange iii and the inner surface 52 of flange 5|, thereby forming line contacts in substantially the same transverse plane which effectively seal the joint between pipes 50 and it against escape of fluid under pressure between their ends.

It will be understood that, as has been mentioned in connection with previously described figures, the wall thickness of pipes 50 and 56 may be other than the thickness shown but these walls should be sufficiently thick to carry flanges BI without breakage when the sealing forces are applied.

In Fig. 'l the pipe 65 has a flared end portion and a substantially cylindrical lip 01. The outer surface 60 of the flared portion 06 is conical, is inclined at an angle of about 45 degrees to the longitudinal center line of the pipe and its baseis near the lip portion 01. The coupling 00 has a flange 10 threaded to receive studs II which carry nuts 12. The coupling is provided with an annular groove 13 to receive the lip 01 and part of the flared portion II of pipe 05. The inner surface ll of this groove I3 is inclined to engage the inner surface of flared portion 65 of pipe 05.

The retaining and sealing ring 15 is quite like ring II of Fig. l and 60 of Fig. 6. It has a sealing flange 10 with an outer surface H to engage surface I0 of groove 13 in coupling 50 and an inner conical surface I! which is inclined at an angle of approximately 44 degrees to the longitudinal center line of pipe 55.

When the ring 15 is urged into groove 13 the flange I5, near its thin end, makes substantially line contacts with surfaces 10 and '68 and thereby eifectively seals against escape of fluid under pressure through groove 13.

It will be note-d that outer surface 11 of flange I0 is slightly conical and that the flange 10 may be reformed radially inward to a small extent before the surface I0 of groove 13 will engage surface 11 of flange 10 for the full overlapping axial lengths of those surfaces. When nuts 12 urge ring I toward flange force is exerted in the direction of arrow A, and force is exerted on the flange as indicated by arrow B. Since the groove 13 is fairly deep, the tendency of these forces is to bend or deform the flange substantially on line C with coincident movement of flange I0 along the line generally indicated by arrow D. Any tendency of flange I0 to bend along line C and move in the direction of arrow D, will result in greater pressure being exerted by the flange I0 on flange 18 of ring 15, and by the latter flange on conical surface 50 of flared portion 66 of pipe 05. Thus, as the sealing producing force exerted on ring increases beyond the amount necessary to cause deflection 01' flange I0, the sealing action increases. Furthermore, this sealing action also increases when forces are applied to pipes 65 and 09 in a direction tending to separate them axially from one another.

In Fig. 8 the pipe 00 has a flared portion BI and a lip portion 02. The outer surface 83 of flared portion 0| is conical, is inclined at an angle of about 45 degrees to the longitudinal center line of pipe 00 and its base is near the lip portion 02. The lip portion 02 and part of the flared portion SI of pipe 00 extend into an annular groove 00 in pipe 05, part 06 of the inner surface of this groove bearing against the inner surface of the flared portion SI of tube 00. Pipe 05 has an exteriorly threaded flange portion 01 to receive an interiorly threaded ring 08 which has an inwardly projecting flange 09 to abut against the thick end of seal ring 90 which projects into the annular space between surface ill of groove 04 and conical surface 03 of flared portion II of pipe 00. The outer and inner surfaces 02 and 03 of ring 90 are conical, their bases being near the thin and of the ring and the inclination of spaces of approximately one degree were formed on either side of the ring with the opposed surfaces of flange 01 and flared portion 0| of pipe 00. When ring 00 is turned to urge ring 00 into groove 04 substantially line contacts are made between the outer and inner surfaces of ring 30 with the opposed surfaces SI and 03 and the joint is effectively sealed against escape of fluid under pressure between the pipe ends. As has just been described in connection with the apparatus of Fig. 7, pressure exerted by ring on seal ring may deform flange 01 substantially along line E. The right-hand sides of the threads on flange Ill are disposed substantially at right angles to the direction of movement of the flange when it is deflected about line E. By reason of this arrangement of threads sealing forces tending to deform flange 01 result in increased sealing effect between ring 00 and flange 01 and pipe 00; and the same result occurs when forces are applied to the pipes tending to separate them axially from one another.

In Fig. 9 pipe I00 has a flared end IOI having a conical outer surface I02 and a lip portion I3 having substantially cylindrical outer and inner surfaces I00 and I05. The coupling I06 has an axially extending groove with cylindrical side walls to receive the lip portion I03 and to support it internally by engaging with surface I04 of the latter. Conical surface I02 of pipe I00 is inclined at an angle of about 45 degrees to the longitudinal axis of the pipe while surface III is inclined at 43 degrees. Coupling I00 carries a plurality of studs I01 similar to those shown in Figs. 1 and 6 and a retaining ring I00 is mounted on those studs for movement toward the coupling I06 by actuation of nuts I00 on studs I01.

A sealing ring H0 is positioned between the conical surface I02 of pipe I00 and the opposed cylindrical surface of coupling I06. The inner surface III of ring H0 is conical and inclined at an angle of about two degrees to the surface I02, the bases of conical surfaces I02 and III being engageable on a circumferentially continuous line near the thin edge of ring III. Between the sealing ring H0 and retaining ring I00 two deformable packing rings II2 are disposed.

When the pipe and coupling are assembled as shown in this figure and retaining ring I00 is pressed against the adjacent packing II2 the two packlngs I I2 are pressed together and against the adjacent end of the sealing ring 0 with the result that the conical surface iII engages the conical surface I02 and is deflected outwardly into contact with the opposed cylindrical surface of coupling I06. The result of this action is the establishment of two substantially line contacts between the outer and inner surfaces of ring 0 near its thin edge with the coupling and with the pipe. Pressure applied by ring I08 to packings I I2 deforms them radially outwardly and inwardly into sealing contact with the outer surface of pipe H0 and the opposed cylindrical surface of cou- I35 which is substantially cylindrical and an opposed surface I 35 which may be slightly curved as shown. The flared end I3I of pipe I30 projects into the space between surfaces I35 and I". Coupling I34 is provided with studs I31 and a retaining ring I38 thereon, both quite like the studs and rings in Fig. 9. Sealing ring I39 has a substantially cylindrical outer surface and a curved but substantially conical inner surface Mil. The radius of curvature of surface III] is slightly greater than that of surface I33 so that an angular space of approximately 1 or 2 degrees exists between ring I39 and portion I3I of the pipe when the two are in assembled position under light pressure. Packing Ill is disposed between the retaining ring I38 and sealing ring I39 and resembles in material and operation the packings III and I25 of Fig. 9.

When ring I38 exerts pressure on packing IlI sealing ring I39 is pressed into contact near its thin edge with surface I33 of pipe I30 and is also deflected outwardly into contact with surface I" of coupling I34. These two contacts are circumferentially continuous, substantially line contacts and are located approximately in a plane extending transversely of the longitudinal center line of pipe I30.

It will be understood that the flange portion I6 of ring Id of Figs. 1 and 2 need not be cut away to receive ring I8 but that on the contrary ring I4 of those flgures may be substantially like ring of Fig. '7. Correspondingly it will be understood that ring 60 of Fig, 6 or ring 15 of Fig. 7 may be cut away and provided with a ring of different material as is illustrated by ring III in Figs. 1 and 2. Indeed the sealing rings of Figs. 3, 4, 5, 8 and 9 may similarly be provided with harder metal portions. Also it will be understood that retainer rings of the screw threaded type may be substituted for those of the stud carried type and vice versa and that retainer rings of forms other than those here illustrated may also be used when desired.

It wil1 also be understood that the angularity.

of the conical surfaces in each of the foregoing embodiments of the invention may vary within wide limits. In Fig. 4 the angularity of surface 32 is 18 degrees while in Fig. l the angularity of surface II is 44 degrees. The range of angularities should not be less than approximately 15 degrees or greater than approximately 75 degrees except under special conditions and angularities between 30 degrees and 60 degrees are preferred for most conditions and applications. I

Having thus described several embodiments of the present invention so that those skilled in the art may be able to understand and practice the present invention, I state that what I desire to -ecu1'e by Letters Patent is defined in what is laimed:

What is claimed is:

l. A fluid seal comprising a body having an opening and a rigid projection having a substantially cylindrical surface surrounding said opening, a member aligned with said opening and having an outer conical surface'disposed within said cylindrical surface, an annular, wedgeshaped, sealing ring having an inner surface inclined at an angle of approximately 2 to said conical surface, said ring making circumferential fluid sealing contact near its thinner end in substantially the same transverse plane with said cylindrical and conical surfaces, the contact of said ring with the said conical surface being substantially only a line contact when fluid pressure in the body is low and increasing in width as fluid 8 pressure in the body increases, and means secured to the body for maintaining said ring in said sealing contact with said member and body.

2. A fluid seal comprising a body having an opening, an annular abutment surface surrounding said opening, and a rigid projection having a. cylindrical surface surrounding said abutment surface, a pipe aligned with said opening, having an inner surface supported on said abutment surface and having an outer conical surface disposed within said cylindrical surface, an annular wedge-shaped sealing ring having an inner surface inclined at an angle of approximately 2 to said conical surface, said ring making circumferential fluid sealing contact near its thinner end in substantially the same transverse plane with said cylindrical and conical surfaces, the contact of said ring with the said conical surface being substantially only a line contact when fluid pressure in the pipe is low and increasing in width as fluid pressure in the pipe increases, and means secured to the body for maintaining said ring in said sealing contact with said pipe and body.

3, A fluid seal comprising a body having an opening, a conical abutment surface surrounding said opening, and a rigid projection having a cylindrical surface surrounding said abutment surface, a pipe aligned with said opening having an inner conical surface making circumferential sealing contact with said abutment surface, and having an outer conical surface disposed within said cylindrical surface, an annular, wedgeshaped, sealing ring having an inner surface inclined at an angle of approximately 2 to said outer conical surface, said ring making circumferential, fluid sealing contact near its thinner end in substantially the same transverse plane with said cylindrical and conical surfaces. the contact of said ring with the said conical surface being substantially only a line contact when fluid pressure in the pipe is low and increasing in width as fluid pressure in the pipe increases, and means secured to the body for maintaining said ring in sealing contact with said pipe and body.

4. A fluid seal comprising a body having an opening and a rigid projection having a substantially cylindrical surface surrounding said opening, a member aligned with said opening and having an outer conical surface disposed within said cylindrical surface, an annular, wedgeshaped, sealing ring having an inner surface inclined at an angle of approximately 2 to said conical surface, said ring making circumferential fluid sealing contact near its thinner end in substantially the same transverse plane with said cylindrical and conical surfaces, the contact of said ring with the said conical surface being substantially only a line contact when fluid pressure in the body is low and increasing in width as fluid pressure in the body increases, deformable packing (between said cylindrical and conical surfaces at the thicker end of said ring), at the thicker end of said ring and between said member and the cylindrical surface, and means secured to the body for pressing said packing against said ring and deforming the packing into sealing contact with said cylindrical (and conical surfaces) surface and said member and for maintaining said ring in said sealing contact with said member and body.

5. A fluid seal comprising a unitary body having a recess defined in part by a substantially cylindrical surface and by a second surface disposed at an angle thereto, a member extending into said recess and having an outer conical surface opposed to said cylindrical surface, said body and member partly defining a cham r for fluid under pressure, an annular wedge-shapedsealing ring in the recess about said member, said ring having an outer surface making an outer, circumferential sealing contact with said cylindrical surface and having a conical inner surface inclined at a small angle to the outer conical surface of said member and making an inner, circumferential, fluid sealing contact near its thinner end with said outer conical surface, said inner contact being substantially only a line contact when fluid pressure in the body is low and increasing in width as the fluid pressure increases, and means connected to the body for maintaining the ring in said sealing contact with said member and said body.

6. A fluid seal comprising a unitary body having a recess defined in part by a substantially cylindrical surface and by a second surface disposed at an angle thereto, a member extending into said recess and having an outer conical surface opposed to said cylindrical surface, said body and member partly defining a chamber for fluid under pressure, an annular, wedge-shaped sealing ring in said annular space and about said member, said ring defining a small angle with one of said cylindrical and conical surfaces, and making an outer, circumferential sealing contact with the said cylindrical surface, and making an inner, circumferential, fluid-sealing contact with the outer conical surface of said member, said contacts being substantially only line contacts when fluid pressure in the body is low and increming in width as the fluid pressure increases, and means connected to the body for maintaining the ring in said sealing contact with said member and said body.

7. A fluid seal comprising a unitary body having a recess defined in part by a substantially cylindrical surface and by a second surface disposed at an angle thereto, a member extending into said recess and having an outer conical surface opposed to said cylindrical surface, said body and member partly defining a chamber for fluid under pressure, an annular wedge-shaped sealing ring in said annular space and about said member, said ring defining a small angle with each of said cylindrical and conical surfaces, and making an outer, circumferential sealing contact with the said cylindrical surface, and making an inner, circumferential, fluid-sealing contact with the outer conical surface of said member, said contacts being substantially only line contacts when fluid pressure in the body is low and increasing in width as the fluid pressure increases, and means connected to the body for maintaining the ring in said sealing contact with said member and said body.

JAMES C. HOBBS.

No references cited.

Certificate of Correction Reissue No. 23,137 July 20, 1949 JAMES C. HOBBS It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 8, lines 61 and 62, strike out "(between said cylindrical and conical surfaces at the thicker end of said ring),; line 67, strike out (and conical surfaces);

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 23rd day of May, A. D. 1950.

THOMAS F. MURPHY Am'atant Omissions? of PM. 

